1. Field of the Invention
This invention relates to motion controllers, and more particularly, to re-configurable drives in a motion controller system.
2. Description of the Related Art
Automated motion control involves precisely controlling the movement of a device or system. Automated motion control is widely used in many different types of applications, including applications in the fields of industrial automation, process control, test and measurement, robotics, and integrated machine vision, among others. A typical automated motion system includes components such as the moving mechanical device(s), a motor with feedback and motion I/O, a motor drive unit, a motion controller, and software to interact with the motion controller.
The motor is commonly a stepper motor or a servo motor. Stepper motors are discrete motion devices that move to positions that relate directly to the number of input control pulses, at a velocity that relates directly to the pulse rate. Servo motors are continuous motion devices that use feedback signals to provide position and velocity control in a closed-loop environment. Motors typically have many wire coils oriented in specific magnetic positions within their housing. By pulsing or steadily controlling current through different motor coils in a known pattern, electromagnetic fields develop in the motor, causing incremental or continuous motion.
The motion controller is often a motion control plug-in board that is connected to an expansion slot or bus of a computer system. The motion controller generates control signals to control the motor and may have various processing components, such as a CPU, DSP, and/or FPGA for performing tasks related to the motion control. A motor drive is typically located between the motion controller and the motor. Motor drive power devices convert the control signals generated by the motion controller into power signals that are provided to the motor connected to the drive.
Communications between the motion controller and the drive are often disrupted when a drive is swapped or a motion controller is replaced. This disruption often requires undesirable reprogramming of the motion controller system because the drive is typically fixed in its communication settings and is not configurable beyond its initial factory communication settings.
FIG. 1A illustrates a block diagram of a prior art motion controller 802 and drive system 804 that uses a breakout box 806 for communications therebetween. The motion controller 802 includes all the digital and analog I/O built into it. This configuration necessitates use of the breakout box 806 for at least the reason that the motion controller 802 and the drive 804 communicate across an analog cable. Also illustrated is a motor 808 that is to be controlled by the motion controller 802. To accommodate appropriate signal adjustment in the system, the motor 808 supplies feedback signals to the drive 804 which enable the drive 804 to indicate to the breakout box 806 the current condition of the motor 808. In some embodiments, the feedback from the motor 808 may travel directly from the motor 808 to the breakout box 806 or even pass through the breakout box 806 directly to the motion controller 802.
FIG. 1B illustrates a block diagram of a prior art distributed motion controller system 820. A motion controller 822 is illustrated with an intelligent drive 824 that is connected via a digital bus 826. The digital bus 826 is deterministic and the digital and analog I/O is built into the intelligent drive 824. In this type of a system, multiple drives may be daisy chained together. A motor 828 is illustrated having feedback to the intelligent drive 824. The feedback, similar to the FIG. 1A embodiment, supports adjustments in signals that are sent from the motion controller 822 to accommodate changing motor requirements. However, the motion controller system 820 introduces new problems such as the communication protocol between the motion controller 822 and the intelligent drive 824. As motion controller manufacturers and drive manufacturers have traditionally been separate entities having different expertise, there is no communication protocol standard with which everyone agrees. This has resulted in the conventional motion system of FIG. 1A to still be the most popular option.
Many other problems and disadvantages of the prior art will become apparent to one skilled in the art after comparing such prior art with the present invention as described herein.